1. Field of the Invention
This invention relates to search position encoding, and more specifically relates to search position encoding for ultra high density memories for use with general purpose digital computers.
2. Description of the Related Art
In recent years, the need for increasingly greater capacity data storage devices for computers and related devices has generated a wide variety of high density data storage and retrieval systems. One recent proposal based upon extremely high resolution scanning which is possible with scanning tunneling microscope technology is described in U.S. Pat. No. 4,575,822. Such proposals relying upon the tunneling occurrence present when a stylus is placed within approximately 10 Angstroms of a surface of a dielectric storage medium, have resulted in data storage systems that were not ultimately practical for use in a computer memory system. Severe control and indexing problems developed, since the clearance between the stylus and the storage medium must be maintained to extremely close tolerances, on the order of a few Angstroms, if tunneling currents are to be maintained within reasonable dynamic ranges. However, with the development of extremely high resolution piezoelectric translation devices and extremely accurate drive feedback systems, the maintenance of such extremely close tolerances has become possible. Therefore, a need exists for a search position encoding system, for locating and indexing on a substrate to be scanned by a scanning tunneling microscope stylus. It would be desirable to provide a rapid, random access system for storage and retrieval of data which may be constructed without the use of exotic materials or manufacturing techniques. It would further be desirable if such a system could be operable in air, rather than in a vaccum or another highly controlled environment, which is very often conventionally required for devices using tunneling currents.